﻿using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace HttpHelper
{
    class DESUtils
    {
       //默认密钥向量
     private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
     /**//// <summary>
     /// DES加密字符串
     /// </summary>
     /// <param name="encryptString">待加密的字符串</param>
     /// <param name="encryptKey">加密密钥,要求为8位</param>
     /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
     public static string EncryptDES(string encryptString, string encryptKey)
     {
         try
         {           
             byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
             byte[] rgbIV = Keys;
             byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
              DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
              MemoryStream mStream = new MemoryStream();
              CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
              cStream.Write(inputByteArray, 0, inputByteArray.Length);
             cStream.FlushFinalBlock();
             return Convert.ToBase64String(mStream.ToArray());
          }
        catch
         {
             return encryptString;
         }
     }

     /**//// <summary>
    /// DES解密字符串
    /// </summary>
     /// <param name="decryptString">待解密的字符串</param>
     /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
     /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
     public static string DecryptDES(string decryptString, string decryptKey)
     {
         try
         {
             byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
             byte[] rgbIV = Keys;
             byte[] inputByteArray = Convert.FromBase64String(decryptString);
              DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
              MemoryStream mStream = new MemoryStream();
              CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
              cStream.Write(inputByteArray, 0, inputByteArray.Length);
              cStream.FlushFinalBlock();
             return Encoding.UTF8.GetString(mStream.ToArray());
          }
         catch
          {
             return decryptString;
          }
     }
 }
   }

